Channel Jumper wrote:
There is nothing special about 9600 baud @ UHF FM.....

That is of course completely wrong. There is a lot special
about 9600 baud (the G3RUH FSK modem). The main thing it that
it requires modulation from 10 Hz upward, and this causes
trouble when the transceiver uses a single PLL that directly
generates the transmit frequency, and where the modulation is
forced on the PLL VCO voltage. That includes most mobile FM
transceivers from the era when packet was popular.

For good performance on 9600 baud you need a transceiver where
the transmit signal is mixed from a fixed frequency that is
modulated and the variable PLL-generated frequency, as is common
in multimode transceivers, or alternatively use a crystal controlled
transceiver that has no PLL in it.

At our local node we used an ancient AEG/Telefunken crystal
controlled transceiver, it had modulation to DC.
This produced the best eye-pattern on 9600 baud I have ever seen.